1. Field of the Invention
This invention relates to medical instruments. It applies specifically to medical needles used for placing an intravenous catheter into a vein. In the U.S. Patent Office it would be found in a classification for needle tip guards which protect health care workers from accidental needle sticks.
2. Description of the Prior Art
To help prevent health care workers from becoming infected by hepatitis or AIDS or the like from an accidental needle prick, it would be desirable to have a guard which covers the tip of an intravenous needle after use. Many such guards have been previously disclosed for hypodermic needles and syringes in general, but no guard has yet been manufactured specifically when the needle is withdrawn from the catheter.
Generally one of the first steps of an emergency medical procedure or a surgical operation is to insert a catheter into the patient's vein so that plasma, anesthetics, or other medications may be conveniently administered. Typically this involves first inserting a needle and plastic catheter combination and then removing the needle to leave only the plastic catheter in the vein. The possibly contaminated needle must then be further handled and disposed of. Obviously it would be desirable to have a guard automatically enclose the sharp end of the needle when it is withdrawn from the catheter, thus preventing the possibility of infection from an accidental needle prick during subsequent handling.
Vaillancourt (U.S. Pat. No. 4,725,267) shows some needle guards which protect the end of a needle after use, but they are not entirely automatic since a mechanism must be pushed or turned to initiate their operation. Also, they are not intended for use with a catheter.
Jagger, Pearson, and Guyenet (U.S. Pat. No. 4,781,692) show a novel solution to the intravenous needle problem. In their invention the needle is withdrawn from the end of the catheter which is in the vein, but remains inside the catheter tubing. Thus the possibly infected needle need not be dealt with and is simply thrown away with the rest of the catheter apparatus after use. However, relative to a simple plastic catheter and fitting, this leaves a more complex and bulky apparatus attached to the patient which can be very uncomfortable and more difficult to handle. The needle left inside can restrict flow of the fluid to the patient.